Electronic watermark system

• US 6,421,450 B2
• Filed: 02/12/1998
• Issued: 07/16/2002
• Est. Priority Date: 02/12/1997
• Status: Expired due to Term

• Current Assignee: NEC Personal Computers, Ltd. (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Nakano, Hirotaka
• Primary Examiner(s): AHMED, SAMIR ANWAR
• Application Number:
  US09/022,473
• Publication Number:
  US 20010040977A1
• Time in Patent Office: 1,615 Days
• Field of Search: 382/100, 382/232, 382/250, 382/253, 380/54, 380/4, 380/3, 380/19, 380/21, 380/30, 380/42, 380/43, 380/49, 380/50, 380/232, 380/201, 380/203, 380/200, 705/56, 705/72, 705/75, 705/57, 705/58, 705/59
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00094 involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00557 wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00855 involving a step of exchanging information with a remote server
• CPC Class Codes: G11B 20/00884 involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32165 using cosine transforms
• CPC Class Codes: H04N 1/32277 Compression
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3274 Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 5/781 : on disks or drums
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8063 : using time division multiplex of the PCM audio and PCM video signals

Abstract

An electronic watermark system invisibly embeds watermark information into original image data and the watermarked image data is transferred to a first medium. At the same time. the embedded watermark information is transferred to a second mediums. When a medium questioned is found, its watermark information can be easily identified by searching the second medium. Alternatively, the watermarked image data and the embedded watermark information are transferred to different storage areas of the same medium, respectively.

Claims

1. A system comprising:

an information generator for generating watermark information;

a combiner for invisibly embedding the watermark information into original image data to produce watermarked image data; and

at least one transfer controller for separately transferring the watermarked image data and the watermark information received from the information generator to a first storage medium and a second storage medium, respectively and watermark information not including a verification key for decoding the watermark image data wherein the first medium and second medium are physically in the same location;

wherein said transfer controller encrypts the watermark information for storage only in the second medium which is dedicated to the encrypted watermark information so that only the encrypted watermark information is allowed to be read.

2. The system according to claim 1, wherein the at least one transfer controller further transfers medium identification information identifying the first storage medium to the second storage medium.

3. The system according to claim 2, wherein the second storage medium stores the encrypted watermark information and the medium identification information to allow retrieval.

4. The system according to claim 3, wherein the medium identification information is a manufacture serial number of the first storage medium.

10. The system according to claim 1, wherein the information generator generates the watermark information from a plurality of watermark information candidates.

5. A system comprising:

an information generator for generating watermark information;

a combine for invisibly embedding the watermark information into original image data to produce watermarked image data; and

a transfer controller for transferring both the watermarked image data and the watermark information received from the information generator from the combine to a single medium, said watermark information not including a verification key for decoding the watermarked image data;

wherein the transfer controller encrypts the watermark information and transfers encrypted watermark information to the single medium; and

wherein in the single medium is a storage medium having a first storage area for storing the watermarked image data and a second storage area for storing the encrypted watermark information, wherein the second storage area is dedicated to the encrypted watermark information so that only the encrypted watermark information is allowed to be read.

11. The system according to claim 5, wherein the information generator generates the watermark information from a plurality of watermark information candidates.

6. An authorization check system for checking whether a medium questioned is authorized, the medium questioned having a first storage area for storing watermarked image data and a second storage area for storing encrypted watermark information, the system comprising:

a watermark extractor for extracting said encrypted watermark information questioned from image data stored in the medium questioned using the original image data and not utilizing a verification key for extracting said encrypted watermark information; and

a checker for checking whether the medium questioned is authorized by comparing the extracted encrypted watermark information with the encrypted watermark information stored in the second storage area of the medium questioned;

wherein the second storage area is dedicated to the encrypted watermark information so that only the encrypted watermark information is allowed to be read.

7. A method for checking whether a medium questioned is authorized, comprising the steps of:

generating watermark information;

generating encrypted watermark information;

invisibly embedding the watermark information into original image date to produce watermarked image data;

transferring the watermarked image data to a first storage area of an authorized storage medium and the encrypted watermark information a second storage area of the authorized storage medium;

extracting watermark information stored in the medium questioned; and

extracting watermark information from watermarked image data stored in the medium question using the original image data and not utilizing a verification key for extracting said watermark information;

checking whether the medium questioned is authorized by comparing the extracted watermark information with watermark information stored in the medium questioned; and

wherein the second storage area is dedicated to the encrypted watermark information so that only the encrypted watermark information is allowed to be read.

8. The method according to claim 7, wherein the authorized medium is a storage medium having a first storage area for storing the watermarked image data and a second storage area. for storing the watermark information, wherein the second storage area to dedicated to the watermark information so that only the watermark information is readable therefrom.

9. The method according to claim 8, wherein the watermark information is encrypted and encrypted watermark information is stored to the authorized medium.

12. The method according to claim 7, wherein the step of generating the watermark information includes the step of selecting the watermark information from a plurality of watermark information candidates.

13. The method according to claim 7, wherein the watermarked image data and the watermark information are transferred over a network.

14. The method according to claim 13, wherein the watermarked image data and the watermark information are transferred over the same network.